Apognophos:
The truth is, I haven't heard the rank and file calling it the AGM at all, only the "annual meeting". "AGM" seems to be a shibboleth on the forum here. I've been careful to avoid saying "AGM" to Witnesses so I don't get funny looks and give away my JWN reading habits.
Of course rank-and-file JWs won't call it the AGM. They probably don't even realise. However:
*** w12 8/15 p. 16 A Meeting Marked by Unity and Thrilling Plans ***
ANNUAL meetings of the Watch Tower Bible and Tract Society of Pennsylvania always generate excitement.
*** w01 1/15 p. 28 How the Governing Body Differs From a Legal Corporation ***
ANNUAL meetings of the Watch Tower Bible and Tract Society of Pennsylvania have been held since January of 1885.
Though they've provided a video link to other locations this year (for the first time ever as far as I'm aware), in reality it's the yearly meeting that is actually attended by the members of the Watch Tower Society corporation. Corporations have annual general meetings.
You also won't hear rank-and-file JWs say that the baptism questions are intended as a contract, or that their meetings for worship are actually indoctrination. JWs love their own special semantics.
Back in reality, it was part of the Watch Tower Society's AGM. But yes, if you're dealing with JWs incognito, you'll want to call it Jehovah's Witnesses' annual meeting™ (even though it's the first most JWs have ever seen) and not the AGM (and certainly not the AGM of a corporation).